Ohio State University Extension entomologists have issued an alert to watch for Western bean cutworm egg masses and larvae, which have been found in Ohio for the first time since the trapping of Western bean cutworm moths in corn began in 2006.
In a Purdue University Extension release, entomologist Andy Michel said Indiana saw damage in 2007 with economic damage following shortly thereafter. In Michigan, the first damage was found in 2007 and economic damage occurred in 2009. In Ontario the first moth was caught in 2008, and the first damage was found last year.
Western bean cutworm is a common pest of Western corn-producing states that is rapidly expanding eastward and finding a niche throughout the Midwest. The number of adult moths trapped in Ohio each year has been steadily increasing.
“The infestation of egg masses and larvae was light, but this just verifies that we won’t see this pest decreasing in the coming years and growers will really have to start scouting for it each season,” Michel said.
In 2006, entomologists caught three moths in the traps. In 2007, six were caught. That number jumped to 150 in 2008 and to 550 in 2009. This year, that number has skyrocketed to 1,834 since July 20.
Though the yield losses in Ohio cornfields have not yet been determined, research in Western states has shown that yield losses can be significant. In Nebraska, yield losses from one larva per corn plant at dent stage were estimated at 3.7 bushels per acre. In Colorado, yield losses were estimated at 30 percent to 40 percent in plants with heavily infested ears. Feeding can also contribute to secondary injury from diseases.